Standard Specifications for Road, Bridge, and Municipal Construction 2020 (M 41-10)

Page 6-140

Steel Structures

6-03.3(7) Shop Plans

The Contractor shall submit all shop detail plans for fabricating the steel as Type 2
Working Drawings.

If these plans will be submitted directly from the fabricator, the Contractor shall so notify
the Engineer in writing.

No material shall be fabricated until: (1) the Working Drawing review is complete, and (2)
the Engineer has accepted the materials source.

Before physical completion of the project, the Contractor shall furnish the Engineer one
set of reproducible copies of the as built shop plans. The reproducible copies shall be
clear, suitable for microfilming, and on permanent sheets that measure no smaller than
11 by 17 inches. Alternatively, the shop drawings may be provided in an electronic format
with the approval of the Engineer.

6-03.3(7)A

Erection Methods

Before beginning to erect any steel Structure, the Contractor shall submit Type 2E
Working Drawings consisting of the erection plan and procedure describing the methods
the Contractor intends to use.

The erection plan and procedure shall provide complete details of the erection process
including, at a minimum, the following:
1. Temporary falsework support, bracing, guys, deadmen, and attachments to other

Structure components or objects;

2.  Procedure and sequence of operation;
3.  Girder stresses during progressive stages of erection;
4.  Girder masses, lift points, and lifting devices, spreaders, glommers, etc.;
5.  Crane(s) make and model, mass, geometry, lift capacity, outrigger size and reactions;
6.  Girder launcher or trolley details and capacity (if intended for use); and
7.  Locations of cranes, barges, trucks delivering girders, and the location of cranes and

outriggers relative to other Structures, including retaining walls and wing walls.

As part of the erection plan Working Drawings, the Contractor may submit details of an
engineered and fabricated lifting bracket bolted to the girder top flanges providing the
following requirements are satisfied:
1. The lifting bracket shall be engineered and supporting calculations shall be submitted

with the erection plan;

2. The calculations shall include critical stresses in the girder including local stresses in

the flanges at lifting bracket locations;

3. The calculations shall include computation of the lifting bracket and associated bolt

hole locations and the expected orientation of the girder during picking operation;

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4. The lifting bracket shall be load tested and certified for a load at least 2 times the

working load and at all angles it will be used (angle of load or rigging). Certification
documentation from a previous project may be submitted;

5. Bolt holes in girders added for the lifting bracket connections shall be shown in

the shop plans and shall be drilled in the shop. Field drilling of bolt holes for lifting
brackets will not be permitted;

6. Bolt holes in girder top flanges shall be filled with high strength bolts after erection

in accordance with

Section 6-02.3(17)K

The erection plan shall include drawings, notes, catalog cuts, and calculations clearly
showing the above listed details, assumptions, and dimensions. Material properties,
Specifications, structural analysis, and any other data used shall also be included.

6-03.3(8) Substitutions

The Contractor shall not substitute sections that differ from Plan dimensions unless
the Engineer approves in writing. If the Contractor requests and receives approval to
substitute heavier members, the Contracting Agency shall not pay any added cost.

6-03.3(9) Handling, Storing, and Shipping of Materials

Markings applied at the mill shall distinguish structural low alloy steel from structural
carbon steel. The fabricator shall keep the two classes of steel carefully separated.

Before fabrication, all material stored at the fabricating plant shall be protected from
rust, dirt, oil, and other foreign matter. The Contracting Agency will accept no rust-pitted
material.

After fabrication, all material awaiting shipment shall be subject to the same storage
requirements as unfabricated material.

All structural steel shall arrive at the job in good condition. As the Engineer requires,
steel damaged by salt water shipment shall be thoroughly cleaned by high pressure water
flushing, chemical cleaning, or sandblasting, and repainted with the specified shop coat.

All material shall be stored so as to prevent rust and loss of small parts. Piled material
shall not rest on the ground or in water but on skids or platforms.

The loading, transporting, unloading, and piling of the structural steel material shall be so
conducted that the metal will be kept clean and free from injury from rough handling.

In field assembly of structural parts, the Contractor shall use methods and equipment
not likely to twist, bend, deform, or otherwise injure the metal. Any member slightly bent
or twisted shall be corrected before it is placed. The Contracting Agency will reject any
member with serious handling damage.

Girder sections shall be handled so as to prevent damage to the girders. If necessary, the
Contractor shall provide temporary stiffeners to prevent buckling during erection.

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6-03.3(10) Straightening Bent Material

If the Engineer permits in writing, plates, angles, other shapes, and built-up members may
be straightened. Straightening methods shall not fracture or injure the metal. Distorted
members shall be straightened mechanically. A limited amount of localized heat may
be applied only if carefully planned and supervised, and only in accordance with the
heat-straightening procedure Working Drawing submittal.

Parts to be heat-straightened shall be nearly free from all stress and external forces
except those that result from the mechanical pressure used with the heat.

After straightening, the Contractor shall inspect the member for fractures using a method
proposed by the Contractor and accepted by the Contracting Agency.

The Contracting Agency will reject metal showing sharp kinks and bends.

The procedure for heat straightening of universal mill (UM) plates by the mill or the
fabricator shall be submitted as a Type 2 Working Drawing.

6-03.3(11) Workmanship and Finish

Workmanship and finish shall be first-class, equaling the best practice in modern bridge
fabrication shops. Welding, shearing, burning, chipping, and grinding shall be done neatly
and accurately. All parts of the Work exposed to view shall be neatly finished.

Wherever the Plans show a surface finish symbol, the surface shall be machined.

6-03.3(12) Falsework

All falsework shall meet the requirements of

Section 6-02

6-03.3(13) Fabricating Tension Members

Plates for main load-carrying tension members or tension components of flexural
members shall be:
1. Blast cleaned entirely or blast cleaned on all areas within 2 inches of welds to

SSPC-SP6, Commercial Blast Cleaning; and

2. Fabricated from plate stock with the primary rolling direction of the stock parallel to

the length of the member, or as shown in the Plans.

6-03.3(14) Edge Finishing

All rolled, sheared, and thermal cut edges shall be true to line and free of rough corners
and projections. Corners along exposed sheared or cut edges shall be broken by
light grinding or another method acceptable to the Engineer to achieve an approximate

1/16-inch chamfer or rounding.

Sheared edges on plates more than ⅝ inch thick shall be planed, milled, ground, or thermal
cut to a depth of at least ⅛ inch.

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Re-entrant corners or cuts shall be filleted to a minimum radius of 1 inch.

Exposed edges of main load-carrying tension members or tension components of flexural
members shall have a surface roughness no greater than 250-micro inches as defined by
the American National Standards Institute, ANSI B46.1, Surface Texture. Exposed edges
of other members shall have surface roughness no greater than 1,000-micro inches.

The Rockwell hardness of thermal-cut edges of structural low alloy or high-strength
steel flanges, as specified in Sections

9-06.2

and

9-06.3

, for main load-carrying tension

members or tension components of flexural members shall not exceed RHC 30. The
fabricator shall prevent excessive hardening of flange edges through preheating, post
heating, or control of the burning process as recommended by the steel manufacturer.

Hardness testing shall consist of testing thermal-cut edges with a portable hardness
tester. The hardness tester, and its operating test procedures, shall be submitted as a Type
1 Working Drawing. The hardness tester shall be convertible to Rockwell C scale values.

At two locations, two tests shall be performed on each thermal-cut edge, one each within
¼ inch of the top and bottom surfaces. The tests shall be located ¼ the length of each
thermal-cut edge from each end of the cut. If one or more readings are greater than RHC
30, the entire length of the edge shall be ground or machined to a depth sufficient to
provide acceptable readings upon further retests. If thermal-cutting operations conform
to procedures established by the steel manufacturer, and hardness testing results are
consistently within acceptable limits, the Engineer may authorize a reduction in the
testing frequency.

6-03.3(15) Planing of Bearing Surfaces

Ends of columns that bear on base and cap plates shall be milled to true surfaces and
accurate bevels.

When assembled, caps and base plates of columns and the sole plates of girders and

trusses shall have a fit tolerance within 1/32 inch for 75 percent of the contact area.

If warped or deformed, the plates shall be heat straightened, planed, or corrected in
some other way to produce accurate, even contact. If necessary for proper contact,
bearing surfaces that will contact other metal surfaces shall be planed or milled.
Surfaces of warped or deformed base and sole plates that will contact masonry shall be
rough finished.

On the surface of expansion bearings, the cut of the planer shall be in the direction of
expansion.

Where mill to bear is specified in the Plans, the bearing end of the stiffener shall be flush
and square with the flange and shall have at least 75 percent of this area in contact with
the flange.

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6-03.3(16) Abutting Joints

Abutting ends of compression members shall be faced accurately so that they bear evenly
when in the Structure. On built-up members, the ends shall be faced or milled after
fabrication.

Ends of tension members at splices shall be rough finished to produce neat, close joints.
A contact fit is not required.

6-03.3(17) End Connection Angles

On floorbeams and stringers, end connection angles shall be flush with each other and
set accurately in relationship to the position and length of the member. Unless the Plans
require it, end connection angles shall not be finished. If, however, faulty assembly

requires them to be milled, milling shall not reduce thickness by more than ¹/

inch.

6-03.3(18) Built Members

The various pieces forming one built member shall be straight and close fitting, true to
detailed dimensions, and free from twists, bends, open joints, or other defects.

When fabricating curved girders, localized heat or the use of mechanical force shall not be
used to bend the girder flanges about an axis parallel to girder webs.

6-03.3(19) Hand Holes

Hand holes, whether punched or cut with burning torches, shall be true to sizes and
shapes shown in the Plans. Edges shall be true to line and ground smooth.

6-03.3(20) Lacing Bars

Unless the Plans state otherwise, ends of lacing bars shall be neatly rounded.

6-03.3(21) Plate Girders

6-03.3(21)A

Web Plates

If web plates are spliced, gaps between plate ends shall be set at shop assembly to

measure ¼ inch, and shall not exceed ⅜ inch.

6-03.3(21)B Vacant
6-03.3(21)C

Web Splices and Fillers

Web splice plates and fillers under stiffeners shall fit within ⅛ inch at each end. In

lieu of the steel material specified in the Plans or Special Provisions, the Contractor
may substitute ASTM A1008 or ASTM A1011 steel for all filler plates less than ¼ inch
thickness, provided that the grade of filler plate steel meets or exceeds that of the
splice plates.

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6-03.3(22) Eyebars

Eyebars shall be straight, true to size, and free from twists or folds in the neck or head
and from any other defect that would reduce their strength. Heads shall be formed by
upsetting, rolling, or forging. Dies in use by the manufacturer may determine the shape of
bar heads if the Engineer approves. Head and neck thickness shall not overrun by more

than ¹/

inch. Welds shall not be made in the body or head of any bar.

Each eyebar shall be properly annealed and carefully straightened before it is bored.
Pinholes shall be located on the centerline of each bar and in the center of its head. Holes
in bar ends shall be so precisely located that in a pile of bars for the same truss panel the
pins may be inserted completely without driving. All eyebars made for the same locations
in trusses shall be interchangeable.

6-03.3(23) Annealing

All eyebars shall be annealed by being heated uniformly to the proper temperature, then
cooled slowly and evenly in the furnace. At all stages, the temperature of the bars shall be
under full control.

Slight bends on secondary steel members may be made without heat. Crimped web
stiffeners need no annealing.

6-03.3(24) Pins and Rollers

Pins and rollers shall be made of the class of forged steel the Plans specify. They shall be
turned accurately to detailed dimensions, smooth, straight, and flawless. The final surface
shall be produced by a finishing cut.

Pins and rollers 9 inches or less in diameter may either be forged and annealed or made of
cold-finished carbon steel shafting.

Pins more than 9 inches in diameter shall have holes at least 2 inches in diameter bored
longitudinally through their centers. Pins with inner defects will be rejected.

The Contractor shall provide pilot and driving nuts for each size of pin unless the Plans
state otherwise.

6-03.3(24)A

Boring Pin Holes

Pin holes shall be bored true to detailed dimensions, smooth and straight, and at right
angles to the axis of the member. Holes shall be parallel with each other unless the Plans
state otherwise. A finishing cut shall always be made.

The distance between holes shall not vary from detailed dimensions by more than

1/32 inch. In tension members, this distance shall be measured from outside to outside of

holes; in compression members, inside to inside.

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6-03.3(24)B

Pin Clearances

Each pin shall be 1/50 inch smaller in diameter than its hole. All pins shall be numbered after

being fitted into their holes in the assembled member.

6-03.3(25) Welding and Repair Welding

Welding and repair welding of all steel bridges shall comply with the AASHTO/AWS
D1.5M/D1.5, latest edition, Bridge Welding Code. Welding and repair welding for all
other steel fabrication shall comply with the AWS D1.1/D1.1M, latest edition, Structural
Welding Code. The requirements described in the remainder of this section shall prevail
whenever they differ from either of the above welding codes.

The Contractor shall weld structural steel only to the extent shown in the Plans. No
welding, including tack and temporary welds shall be done in the shop or field unless the
location of the welds is shown on the approved shop drawings reviewed and accepted by
the Engineer.

Welding procedures shall accompany the shop drawing Working Drawing submittal. The
procedures shall specify the type of equipment to be used, electrode selection, preheat
requirements, base materials, and joint details. When the procedures are not prequalified
by AWS or AASHTO, evidence of qualification tests shall be submitted.

Welding shall not begin until completion of the shop plan Working Drawing review as
required in

Section 6-03.3(7)

. These plans shall include procedures for welding, assembly,

and any heat-straightening or heat-curving.

Any welded shear connector longer than 8 inches may be made of two shorter shear
connectors joined with full-penetration welds.

In shielded metal-arc welding, the Contractor shall use low-hydrogen electrodes.

In submerged-arc welding, flux shall be oven-dried at 550ºF for at least 2 hours, then
stored in ovens held at 250ºF or more. If not used within 4 hours after removal from a
drying or storage oven, flux shall be redried before use.

Preheat and interpass temperatures shall conform to the applicable welding code as
specified in this section. When welding main members of steel bridges, the minimum
preheat shall not be less than 100ºF.

If groove welds (web-to-web or flange-to-flange) have been rejected, they may be
repaired no more than twice. If a third failure occurs, the Contractor shall:
1. Trim the members, if the Engineer concurs, at least ½ inch on each side of the weld;

2. Replace the members at no expense to the Contracting Agency.

By using extension bars and runoff plates, the Contractor shall terminate groove welds
in a way that ensures the soundness of each weld to its ends. The bars and plates shall
be removed after the weld is finished and cooled. The weld ends shall then be ground
smooth and flush with the edges of abutting parts.

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The Contractor shall not:
1.  Weld with electrogas or electroslag methods,
2.  Weld nor flame cut when the ambient temperature is below 20ºF, or
3.  Use coped holes in the web for welding butt splices in the flanges unless the Plans

show them.

6-03.3(25)A

Welding Inspection

The Contractor’s inspection procedures, techniques, methods, acceptance criteria, and
inspector qualifications for welding of steel bridges shall be in accordance with the
AASHTO/AWS D1.5M/D1.5: 2010 Bridge Welding Code. The Contractor’s inspection
procedures, techniques, methods, acceptance criteria, and inspector qualifications for
welding of steel Structures other than steel bridges shall be in accordance with AWS
D1.1/D1.1M, latest edition, Structural Welding Code. The requirements described in
the remainder of this section shall prevail whenever they differ from either of the above
welding codes.

Nondestructive testing in addition to visual inspection shall be performed by the
Contractor. Unless otherwise shown in the Plans or specified in the Special Provisions, the
extent of inspection shall be as specified in this section. Testing and inspection shall apply
to welding performed in the shop and in the field.

After the Contractor’s welding inspection is complete, the Contractor shall allow the
Engineer sufficient time to perform quality assurance ultrasonic welding inspection.

6-03.3(25)A1 Visual Inspection

All welds shall be 100 percent visually inspected. Visual inspection shall be performed
before, during, and after the completion of welding.

6-03.3(25)A2 Radiographic Inspection

Complete penetration tension groove welds in Highway bridges shall be 100 percent
radiographically inspected. These welds include those in the tension area of webs, where
inspection shall cover the greater of these two distances: (a) 15 inches from the tension

flange, or (b) ⅓ of the web depth. In addition, edge blocks conforming to the requirements

of AASHTO/AWS D1.5M/D1.5: 2010 Bridge Welding Code Section 6.10.14 shall be used
for radiographic inspection.

The Contractor shall maintain the radiographs and the radiographic inspection report
in the shop until the last joint to be radiographed in that member is accepted by
the radiographer representing the Contractor. Within 2 working days following this
acceptance, the Contractor shall mail the film and two copies of the radiographic
inspection report to the Materials Engineer, Department of Transportation,
PO Box 47365, Olympia, WA 98504-7365.

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6-03.3(25)A3 Ultrasonic Inspection

Complete penetration groove welds on plates

inch and thicker in the following welded

assemblies or Structures shall be 100 percent ultrasonically inspected:
1. Welded connections and splices in Highway bridges and earth retaining Structures,

excluding longitudinal butt joint welds in beam or girder webs.

2. Bridge bearings and modular expansion joints.
3. Sign bridges, cantilever sign Structures, and bridge mounted sign brackets excluding

longitudinal butt joint welds in beams.

4. Light, signal, and strain pole standards, as defined in

Section 9-29.6

A minimum of 30 percent of complete penetration vertical welds on steel column jackets

thicker than 5/16-inch, within 1.50 column jacket diameter of the top and bottom of each

column, shall be inspected. If any rejectable flaws are found, 100 percent of the weld
within the specified limits shall be inspected. The largest column cross section diameter
for tapered column jackets shall constitute one column jacket diameter.

The testing procedure and acceptance criteria for tubular members shall conform to the
requirements of the AWS D1.1/D1.1M latest edition, Structural Welding Code.

6-03.3(25)A4 Magnetic Particle Inspection

1. Fillet and partial penetration groove welds:

At least 30 percent of each size and type of fillet welds (excluding intermittent fillet
welds) and partial penetration groove welds in the following welded assemblies or
Structures shall be tested by the magnetic particle method:
a.  Flange-to-web connections in Highway bridges.
b.  End and intermediate pier diaphragms in Highway bridges.
c.  Stiffeners and connection plates in Highway bridges.
d.  Welded connections and splices in earth retaining Structures.
e.  Boxed members of trusses.
f.

Bridge bearings and modular expansion joints.

g. Sign bridges, cantilever sign Structures, and bridge mounted sign brackets.
h. Light, signal, and strain pole standards, as defined in

Section 9-29.6

2. Longitudinal butt joint welds in beam and girder webs:

At least 30 percent of each longitudinal butt joint weld in the beam and girder webs
shall be tested by the magnetic particle method.

3. Complete penetration groove welds on plates 5/16 inch or thinner (excluding steel

column jackets) shall be 100 percent tested by the magnetic particle method. Testing
shall apply to both sides of the weld, if backing plate is not used. The ends of each
complete penetration groove weld at plate edges shall be tested by the magnetic
particle method.

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4. A minimum of 30 percent of complete penetration vertical welds on steel column

jackets 5/16 inch or thinner, within 1.50 column jacket diameters of the top and

bottom of each column, shall be magnetic particle inspected. The largest column
cross section diameter for tapered column jackets shall constitute one column
jacket diameter.

Where 100 percent testing is not required, the Engineer reserves the right to select the
location(s) for testing.

If rejectable flaws are found in any test length of weld in item 1 or 2 above, the full length
of the weld or 5 feet on each side of the test length, whichever is less, shall be tested.
If any rejectable flaws are found in any test length of item 4 above, 100 percent of the
weld within the specified limits shall be inspected.

6-03.3(26) Screw Threads

Screw threads shall be U.S. Standard and shall fit closely in the nuts.

6-03.3(27) High-Strength Bolt Holes

At the Contractor’s option under the conditions described in this section, holes may
be punched or subpunched and reamed, drilled or subdrilled and reamed, or formed by
numerically controlled drilling operations.

The hole for each high-strength bolt shall be ¹/

inch larger than the nominal diameter of

the bolt.

In fabricating any connection, the Contractor may subdrill or subpunch the holes then
ream full size after assembly or drill holes full size from the solid with all thicknesses of
material shop assembled in the proper position. If the Contractor chooses not to use
either of these methods, then the following shall apply:
1. Drill bolt holes in steel splice plates full size using steel templates.
2. Drill bolt holes in the main members of trusses, arches, continuous beam spans,

bents, towers, plate girders, box girders, and rigid frames at all connections
as follows:
a. A minimum of 30 percent of the holes in one side of the connection shall be

made full size using steel templates.

b. A minimum of 30 percent of the holes in the second side shall be made full size

assembled in the shop.

c. All remaining holes may be made full size in unassembled members using steel

templates.

3. Drill bolt holes in crossframes, gussets, lateral braces, and other secondary members

full size using steel templates.

The Contractor shall submit Type 2 Working Drawings consisting of a detailed outline
of the procedures proposed to accomplish the Work from initial drilling through
shop assembly.

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6-03.3(27)A

Punched Holes

For punched holes, die diameter shall not exceed punch diameter by more than ¹/

inch.

Any hole requiring enlargement to admit the bolt shall be reamed. All holes shall be cut
clean with no torn or ragged edges. The Contracting Agency will reject components
having poorly matched holes.

6-03.3(27)B

Reamed and Drilled Holes

Reaming and drilling shall be done with short taper reamers or twist drills, producing
cylindrical holes perpendicular to the member. Reamers and drills shall be directed
mechanically, not hand-held. Connecting parts that require reamed or drilled holes shall
be assembled and held securely as the holes are formed, then match-marked before
disassembly. The Contractor shall provide the Engineer a diagram showing these match-
marks. The Contracting Agency will reject components having poorly matched holes.

Burrs on outside surfaces shall be removed. If the Engineer requires, the Contractor shall
disassemble parts to remove burrs.

If templates are used to ream or drill full-size connection holes, the templates shall be
positioned and angled with extreme care and bolted firmly in place. Templates for reaming
or drilling matching members or the opposite faces of one member shall be duplicates. All
splice components shall be match-marked unless otherwise approved by the Engineer.

6-03.3(27)C

Numerically Controlled Drilled Connections

In forming any hole described in

Section 6-03.3(27)

, the fabricator may use numerically

controlled (N/C) drilling or punching equipment if it meets the requirements in this
Subsection.

The Contractor shall submit Type 1 Working Drawings consisting of a detailed outline of
proposed N/C procedures. This outline shall:
1. Cover all steps from initial drilling or punching through check assembly;
2. Include the specific members of the Structure to be drilled or punched, hole sizes,

locations of the common index and other reference points, makeup of check
assemblies, and all other information needed to describe the process fully.

N/C holes may be drilled or punched to size through individual pieces, or may be drilled
through any combination of tightly clamped pieces.

When the Engineer requires, the Contractor shall demonstrate that the N/C procedure
consistently produces holes and connections meeting the requirements of these
Specifications.

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6-03.3(27)D Accuracy of Punched, Subpunched, and Subdrilled Holes

After shop assembly and before reaming, all punched, subpunched, and subdrilled holes
shall meet the following standard of accuracy. At least 75 percent of the holes in each

connection shall permit the passage of a cylindrical pin ⅛ inch smaller in diameter than

nominal hole size. This pin shall pass through at right angles to the face of the member

without drifting. All holes shall permit passage of a pin ³/

inch smaller in diameter than

nominal hole size. The Contracting Agency will reject any pieces that fail to meet these
standards.

6-03.3(27)E

Accuracy of Reamed and Drilled Holes

At least 85 percent of all holes in a connection of reamed or drilled holes shall show no

offset greater than ¹/

inch between adjacent thicknesses of metal. No hole shall have an

offset greater than ¹/

inch.

Centerlines from the connection shall be inscribed on the template and holes shall be
located from these centerlines. Centerlines shall also be used for accurately locating the
template relative to the milled or scribed ends of the members.

Templates shall have hardened steel bushing inserted into each hole. These bushings may
be omitted, however, if the fabricator satisfies the Engineer (1) that the template will be
used no more than five times, and (2) that use will produce no template wear.

Each template shall be at least ½ inch thick. If necessary, thicker templates shall be used
to prevent buckling and misalignment as holes are formed.

6-03.3(27)F

Fitting for Bolting

Before drilling, reaming, and bolting begins, all parts of a member shall be assembled, well
pinned, and drawn firmly together. If necessary, assembled pieces shall be taken apart to
permit removal of any burrs or shavings produced as the holes are formed. The member
shall be free from twists, bends, and other deformation.
In shop-bolted connections, contacting metal surfaces shall be sandblasted clean before
assembly. Sandblasting shall meet the requirements of the SSPC Specifications for
Commercial Blast Cleaning (SSPC-SP 6).
Any drifting done during assembly shall be no more than enough to bring the parts into
place. Drifting shall not enlarge the holes or distort the metal.

6-03.3(28) Shop Assembly

6-03.3(28)A

Method of Shop Assembly

Unless the Contract states otherwise, the Contractor shall choose one of the five shop
assembly methods described below that will best fit the proposed erection method.
The Contractor shall obtain the Engineer’s approval of both the shop assembly and the
erection methods before Work begins.
1. Full Truss or Girder Assembly – Each truss or girder is completely assembled over the

full length of the Superstructure.

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2. Progressive Truss or Girder Assembly – Each truss or girder is assembled in stages

longitudinally over the full length of the Superstructure.
a. For Trusses – The first stage shall include at least three adjacent truss panels.

Each truss panel shall include all of the truss members in the space bounded
by the top and bottom chords and the horizontal distance between adjacent
bottom chord Joints.

b. For Girders – The first stage shall include at least three adjacent girder shop

sections. Shop sections are measured from the end of the girder to the first
field splice or from field splice to field splice.

c. For Trusses and Girders – After the first stage has been completed, each

subsequent stage shall be assembled to include: at least one truss panel or
girder shop section of the previous stage and two or more truss panels or
girder shop sections added at the advancing end. The previous stages shall be
repositioned if necessary, and pinned to ensure accurate alignment. For straight
sections of bridges without skews or tapers, girders in each subsequent stage
may be assembled to include one girder shop section from the previous stage
and one or more girder shop sections at the advancing end.

If the bridge is longer than 150 feet, each longitudinal stage shall be at least
150 feet long, regardless of the length of individual continuous truss panels or
girder shop sections.

The Contractor may begin the assembly sequence at any point on the bridge
and proceed in either or both directions from that point.

Unless the Engineer approves otherwise, no assembly shall have less than three
truss panels or girder shop sections.

3. Full Chord Assembly – The full length of each chord for each truss is assembled with

geometric angles at the joints. Chord connection bolt holes are drilled/reamed while
members are assembled. The truss web member connections are drilled/reamed to
steel templates set by relating geometric angles to the chord lines.

At least one end of each web member shall be milled or scribed at right angles to its
long axis. The templates at both ends of the member shall be positioned accurately
from the milled end or scribed line.

4. Progressive Chord Assembly – Adjacent chord sections are assembled in the

same way as specified for Full Chord Assembly, using the procedure specified for
Progressive Truss or Girder Assembly.

5. Special Complete Structure Assembly – All structural steel members (Superstructure

and Substructure, including all secondary members) are assembled at one time.

6-03.3(28)B

Check of Shop Assembly

The Contractor shall check each assembly for alignment, accuracy of holes, fit of milled
joints, and other assembly techniques. Drilling or reaming shall not begin until the
Engineer has given approval. If the Contractor uses N/C drilling, this approval must be
obtained before the assembly or stage is dismantled.

Steel Structures

6-03

6-03.3(29) Welded Shear Connectors

Installation, production control, and inspection of welded shear connectors shall conform
to Chapter 7 of the AASHTO/AWS D1.5M/D1.5:2010 Bridge Welding Code. If welded
shear connectors are installed in the shop, installation shall be completed prior to applying
the shop primer coat in accordance with

Section 6-07.3(9)G

. If welded shear connectors

are installed in the field, the steel surface to be welded shall be prepared to SSPC-SP 11,
power tool cleaning, just prior to welding.

6-03.3(30) Painting

All painting shall be in accordance with

Section 6-07

6-03.3(30)A Vacant
6-03.3(30)B Vacant
6-03.3(30)C

Erection Marks

Erection marks to permit identification of members in the field shall be painted on
previously painted surfaces.

6-03.3(30)D Machine Finished Surfaces

As soon as possible and before they leave the shop, machine-finished surfaces on
abutting chord splices, column splices, and column bases shall be covered with grease.
After erection, the steel shall be cleaned and painted as specified.

All surfaces of iron and steel castings milled to smooth the surface shall be painted with
the primer called for in the specified paint system.

While still in the shop, machine-finished surfaces and inaccessible surfaces of rocker or
pin-type bearings shall receive the full paint system. Surfaces of pins and holes machine-
finished to specific tolerances shall not be painted. But as soon as possible and before
they leave the shop, they shall be coated with grease.

6-03.3(31) Alignment and Camber

Before beginning field bolting, the Contractor shall:
1.  Adjust the Structure to correct grade and alignment,
2.  Regulate elevations of panel points (ends of floorbeams), and
3.  Delay bolting at compression joints until adjusting the blocking to provide full and

even bearing over the whole joint.

On truss spans, a slight excess camber will be permitted as the bottom chords are bolted.
But camber and relative elevations of panel points shall be correct before the top chord
joints, top lateral system, and sway braces are bolted.

Page 6-154

Steel Structures

6-03.3(31)A

Measuring Camber

The Contractor shall provide the Engineer with a diagram for each truss that shows
camber at each panel point. This diagram shall display actual measurements taken as the
truss is being assembled.

6-03.3(32) Assembling and Bolting

To begin bolting any field connection or splice, the Contractor shall install and tighten
to snug tight enough bolts to bring all parts into full contact with each other prior to
tightening these bolts to the specified minimum tension. “Snug tight” means either the
tightness reached by (l) a few blows from an impact wrench or (2) the full effort of a
person using a spud wrench.

As erection proceeds, all field connections and splices for each member shall be securely
drift pinned and bolted in accordance with 1 or 2 below before the weight of the member
can be released or the next member is added. Field erection drawings shall specify
pinning and bolting requirements that meet or exceed the following minimums:
1. Joints in Normal Structures – Fifty percent of the holes in a single field connection

and 50 percent of the holes on each side of a single joint in a splice plate shall be
filled with drift pins and bolts. Thirty percent of the filled holes shall be pinned.
Seventy percent of the filled holes shall be bolted and tightened to snug tight. Once
all these bolts are snug tight, each bolt shall be systematically tightened to the
specified minimum tension. “Systematically tightened” means beginning with bolts
in the most rigid part, which is usually the center of the joint, and working out to its
free edges. The fully tensioned bolts shall be located near the middle of a single field
connection or a single splice plate.

2. Joints in Cantilevered Structures – Seventy-five percent of the holes in a single

field connection and 75 percent of the holes on each side of a single joint in a splice
plate shall be filled with drift pins and bolts. Fifty percent of the filled holes shall be
pinned. Fifty percent of the filled holes shall be bolted and tightened to snug tight.
Once all these bolts are snug tight, each bolt shall be systematically tightened to the
specified minimum tension. The fully tensioned bolts shall be located near the middle
of a single field connection or a single splice plate.

Cylindrical erection pins (drift pins) shall be placed throughout each field connection and
each field joint with the greatest concentration in the outer edges of a splice plate or
member being bolted. Drift pins shall be double-tapered barrel pins of hardened steel.

The diameter of the drift pins shall be at least 1/32 inch larger than the diameter of the

bolts in the connection or the full hole diameter.

To complete a joint following one of the methods listed above, the Contractor shall fill
all remaining holes of the field connection or splice plate with bolts and tighten to snug
tight. Once all of these bolts are snug tight, each bolt shall be systematically tightened to
the specified minimum tension. After these bolts are tightened to the specified minimum
tension, the Contractor shall replace the drift pins with bolts tightened to the specified
minimum tension.

Steel Structures

6-03

The Contractor shall complete the joint or connection within ten calendar days of
installing the first bolt or within a duration approved by the Engineer. Any bolts inserted
in an incomplete connection, either loose or tightened snug-tight, which exceed the
specified duration for completing the connection, shall be subject to the following
requirements:
1. Three assemblies for each size and length shall be removed from connection(s) that

are to be tensioned. Rotational capacity tests shall be performed on the removed
assemblies to demonstrate the assembly has sufficient lubricant to be tensioned
satisfactorily.

2. Five assemblies shall be removed from the connection to establish the inspection

torque.

3. In the case of tension controlled bolts, three assemblies shall be removed and tested

in accordance with

Section 6-03.3(33)A

to verify the minimum specified tension can

be achieved prior to shearing of the spline.

Assemblies removed for the purpose of rotational capacity testing, determination of
the inspection torques, or verification of tension controlled bolt performance shall be
replaced with new bolts at no additional expense to the Contracting Agency. To minimize
the number of removed assemblies, the Contractor may combine rotational capacity
testing and inspection torque determination as approved by the Engineer.

The Contractor may complete a field bolted connection or splice in a continuous
operation before releasing the mass of the member or adding the next member. The
Contractor shall utilize drift pins to align the connection. The alignment drift pins shall fill
between 15 and 30 percent of the holes in a single field connection and between 15 and
30 percent of the holes on each side of a single joint in a splice plate. Once the alignment
drift pins are in place, all remaining holes shall be filled with bolts and tightened to snug
tight starting from near the middle and proceeding toward the outer gage lines. Once all
of these bolts are snug tight, the Contractor shall systematically tighten all these bolts to
the specified minimum tension. The Contractor shall then replace the drift pins with bolts.
Each of these bolts shall be tightened to the specified minimum tension.

All bolts shall be placed with heads toward the outside and underside of the bridge. All
high-strength bolts shall be installed and tightened before the falsework is removed.

The Contractor may erect metal railings as erection proceeds. But railings shall not be
bolted or adjusted permanently until the falsework is released and the deck placed.

The Contractor shall not begin painting until the Engineer has inspected and accepted
field bolting.

6-03.3(33) Bolted Connections

Fastener components shall consist of bolts, nuts, washers, tension control bolt assemblies,
and direct tension indicators. Fastener components shall meet the requirements of

Section 9-06.5(3)

. After final tightening of the fastener components, the threads of the

bolts shall at a minimum be flush with the end of the nut.

Standard Specifications for Road, Bridge, and Municipal Construction 2020 (M 41-10) - page 66